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seperating salt from water

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ellywellywoo | 18:44 Thu 22nd Jan 2009 | Science
8 Answers
Hi hope someone out there can help please.
My 11 year old daughter for her homework has to write how to seperate salt from water but at the end there must be a bowl of water and a bowl of salt.
The only way I know is if you evaporate the water but in this case she must end up with the water in a seperate bowl.
Can some one please tell us please.
Many thanks inadvance.
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You're on the right track!

As the water evapourates you need to condense it again and allow it to drip into a bowl.

Can't remember exactly what aparatus we used at school, but steam will condensate on a colder surface, (like the water that runs down the inside of a steamed up window). If the surface is inclined, the water will run down the surface and can be collected below.
Add water to the salt and sand mixture, stir.

Filter sand from the salt solution using a filter paper and funnel.

Boil the salt solution and condense the steam using a liebig condenser (simple distillation)

You're left with a pure water condensate and pure salt
Question Author
Teddio

Sorry not sure I understand. Why would I need to add sand to the equation.? I think her teacher told her she just had to write about salt and water.
Also we are not sure what a liebig condensor is? Maybe I will google it.
Sorry about the sand! If you boil a solution of salt in water in a glass flask , the water will boil at 100 Celsius and turn to steam.
The steam may be condensed back to water by allowing it to make contact with a cold surface. A liebig condenser is an arrangement of two concentric tubes, with cold water flowing in the outer tube and the vapour consensing in the inner tube.
The salt has a very high boiling point and will not evaporate, so will be left behind in the glass flask.
It may help your daughter to get full marks if she spells 'separate' correctly, ellywellywoo :-)
(Unless her teacher is under 40, in which case it will probably make no difference.)
Follow Muppit's advice, but spell 'evaporate' and 'apparatus' correctly. :-)
Teddio is also correct, but is wrong about the boiling point of the salt in water solution. The boiling point of the solution will be slightly higher than 100�C (just as its freezing point will be slightly lower than 0�C). The difference will be very slight, too small to notice, probably, but worth knowing, if you take science seriously.
Question Author
Bert

Its her mother that cant spell not her daughter!!
If you boil a solution of saltwater, eventually the water will evaporate and leave salt in the pan being heated.

If you can somehow fix a cold metal baking tray above the pan of salty water being heated (a few Centimetres above it), with one end angled slightly downwards, the steam will condense on this and run to the lowest end.

Put a bowl beneath the lowest end to catch the condensed water.

I would imagine that a cold marble chopping board would work even better.
I appreciate that the spelling was yours, ellywellywoo, not your daughter's, but you know what they say - "like mother, like daughter" :-)
Please ignore the ravings of a 60-year-old pedant, but hardly anybody seems to be able to spell separate or surprise these days. I know many people think it does not matter - especially on informal sites such as this - but it is quite distracting to see words spelt incorrectly.
Wen ther ar no rools for spelin wee may see newspapuz and buks wiv fonetik spelin. Ynoworamin?

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